Samsung 830 is usually best bang for buck imo. Crucial M4 is also very cheap. They go on sale a lot. Vertex 4 is reasonable as well, good sales. Plextor M5 Pro if you want best of best...also might want to check out the new Corsair Neutron Series. Plextor M3 Pro is also very nice.

Buy.com is selling the Crucial M4 256GB for $199.99 (no code necessary)
They are also selling the 128GB version for $79.99 shipped...and if you don't have an account you can get an additional $5 off your order